Illuminating apparatus.



LT. WUFFY.

ILLUMINATlNG APPARATUS.

APPLlcMroN mw new. ums.

Bamm July-2, '1918.'

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JSEPH T. RFFY, OF ELTTSIBURG-H, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSGRUMENTS, TU HAWTHURNE MANUFACTURING COMPANY, INCORPORATED, 0F BRIDGE WORT,CONNECTICUT, A CORPORATION 03E' CONNECTICUT.

inruil/limewire arrarm'rus.

Specification of Letters atent.

Application led December l, i915. Serial No. 641,512.

.To all 'w from it may concern.;

lie it known that l, Josnrn l. Borri', a

subject ol the llmperor of Austria-Hungary, residing in Pittsburgh,county of Allegheny, State of Pennsylvania, have invented certain newand useful. Improvements in Illuminating Apparatus, of which thefollowing is a specification.

My inventionfrelates. in ,general to lamps for lighting and morespecifically to an apg paratus in which the radiation from the lamp orilluminating* source is treated for the prmluction of a definite limitedfield of illumination. ln anothei` sense the invention relates toiunnovements in the efficiency olE illumination. A further feature ofthe invention an improved arrangement ot' primary and secondaryilluminating sources wlierebv a certain advantageous combina.- tion ol"two interrhangeable fields ot illumination may be secured.

The objects oi" the invention include the prmluction of a parallel beamot light from a source which is concealed from direct observation,whereby the source is visible in but one direction or line, notherobiectis to provide 'For increased economy of illuurination bv transmittingfrom the apparatus only that portion of the illumination which isdesired and restoring to the source so tar as possible, the radiation oflight and heat which is not remescntcd in the de sired flux ot licht. Afurther object is to provide an apparatus in which a selection of thequantity and direction of illumination from a plurality of sources maybe made. ther advantages and objects ot the invention will be apparenttrom a consideration ot an embodiment oii the invention illustrated inthe accompanying drawing4 and rei-'erred to in detail hereinafter.

-laid drawingl represents a central vertical section oiu an automobilebead-light which embodies the invention.

ierrinfr now in detail to said drawing, i@ indicates the illuminatingsource, prefierably an electric incandescent lamp and more sneciiicallyone of the type lrnown as gasilled. in which inert gases, such as forenample nitrogen and argon, are employed Within the bulb to oppose thevapor tension ot' the filament material. The lamp 10 is mounted in asocket 11 suitably, and connected by cable 12 with a. source ot electriccurrent.

Associated with. the illuminating source l() is a concave reflector 13which may for example be substantially parabolic and so located withrespect to the center ot the luminous source as to transmit' the lighttherefrom in the form of a distinct parallelbeam. The reflector 13terminates at such distance from the illuminating source 10 as not tosacrifice the clear limitation of the beam to a parallel condition, thiscondition prescribing about a 52 yangle of incidence as the extreme.This termination oi the parallelsbeam reflector is indicated by the line14 in the drawing. Adjacent the tip of the lamp 10 and in axialalinement theren with7 l employ a tube 15 of opaque material such as forexample, drawn copper tubine. This tube may have a diameterapproximately'equal to that of the lamp bulb and it will be observedthat its inner end or edge 1G defines with thc terminal edge 14 of the,reflector 1.3, an annular opening through which a parallel-imam of lightfrom reflector 13 is delivered. ln order to obscure the direct rayswhich might otherwise escape through this annular space, from lamp 10, lprovide a second reflector 17 ot' spherical curvature. the center ofcurvature beiner the center of lamp 10. This obscuring,r reflector 17thus directs back to the illuminating source any light and heat whichpasses di Patented 1l ully fe,

liti' liti rectly through the annular space defined by tbc cycles 14 and16. lilor convenience ot construction. the reflectors 13 and 17 mayconstitute parts of a unitary sheet metal drawing. these parts being`united by a irusto-conical portion 18 which performs no direct opticalfunction in 'the apparatus. 1t serves however as a convenient mountingfor a lamp 19 which fits into socket Qiand is connected by means oi3cable 21 with a suitable source of electric current. The lo cation oflamp 19 above tbe central horizontal plane o't the reflector 13 andbeneath the spherical reflecting surface 1'? provides for a secondaryilluminationot less candle power, which may be employed alternately tothe 'primary illumination and which will be contined to the emission otlight in a generally downward direction4 as required for example in`manycity ordinances. 'lhe obseuring and reiiecting surface, 17 will preventdirect observation 4oi secondary source 1.9, except below apredetermined level.

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llllb 17, I provide may Surrounding the forward edge of reflector a ringor band 22 within which e conveniently mounted, a glass dislr 23 formedwith an axial stud or post 2ltor the reception of the above mentionedtube 15. rllhe ring 22 may for example Vhe secured to the reliector 19by means of solder or otherwise. To retain the glass disk 23 in itsplace, a cover 25 having a central light aperture 26 commensurate withthe parallel-beam of light, is employed. This cover 25 is provided witha cylindricalportion 2'? which slides upon a similar cylindrical portion28 of a sheet metal rear wall member 29. The inner face 30 of the stud24 may be frosted or rendered opaque to prevent the transmission ofdirect light from the source 10. Vfith the apparatus described it willbe apparent that light from source 10 is transmitted to the exterior ofthe apparatus only in the form of a parallel-beam coming from thereflector 13. ln the case of aeroplanes or other aerial machines, theuse of a vertical beam of light will prevent t-he location of themachine in space by triangulation as the light is'visible only in onedirection. At the same time, in the case of automobile head-lights, theapparatus provides afconcentrated illumination within the i1nmediatepath while returning to the source the heat and light not represented insuch. illumination whereby an important gain in economy is attained. lnthe case of incandescent lamps, the energy thus returned in the form otheat, represents a considerable saving and aids materiali 1 in themaintenance of the desired filament temperature. In the metallic ilamentlamps, the positive temperature coefficient will cause this re- Iusersof the road, for

stored heat to show a drop in current consumption. lt a gastilled lampbe employed, the energy returned represents an important item in thereduction of heat loss arising from the conductivity of the inclosedgas. ln this latter respect the invention will thus be seen to providean important improvement in the use oit' gas illed lamps, residing' inthe return to the lamp of light and heat energy not represented in theuseful illumination.

A lamp forvehicle use, such as automobiles, which .is subject to higspeeds in open country and moderate speeds in crowd- .ed thoroughareswithin city limits, must e of reasonable size, and provided with twoindependently controlled light sources, one oi comparatively largecandle power for fast .driving on country roads and the other ci moremoderate candle power and prefer ablyconcealed to provide a diffusedlight immediately in front ci the vehicle embracing a large area anddevoid ofglare to other moderate speed and crowded thorought'ares, rlhespeed lighting calls for-a powerful and penetre-tt? .opening of t'l'peinture ofthe tllarnent j Laffont/e ing central beam projectingparallel or slightly inclined toward the road and devoid of rays'oflight that are at an angle to the projected beam and which interferewith vision, such as the direct candle power of the light source, orrays that diverge at an angle to the main spherical aberration in thepresent form oi short focus parabolic type of reflectors. A concavereflector, whether spherical or parabolic will handle a light fluir,generally speaking, in proportion to the angle ot light it embraces ct'the light source. Therefore if we assume a given aperture, the shortervthe focus ofthe reflector becomes, the greater will be the light flux.ration of the reflector, however, is greater with a short focus.Desiring visibility and penetration ot the light at a distance, I seekto provide for a relatively long focus, and do so without sacrifice tothe smallness and compact shape of the lamp. AL longer focus rellector,although ot reducedy size of aperture to maintain compactness, may stillbe preferable although it embraces less total light flux L 1n reflectorot the same aper ture and shorter focus. In accordance with this desireto avoid spherical aberration, I employ a reflector of the concavevariety having a relatively long focus and embracing the light sourcebetween the normals approximately 30 degrees and 105 degrees. choose 30degrees because at that angle the spherical candle power of the lightsource will be reflected by the parabolic bcyondthe diameter oi theglobe, that is the return light will not be obscured by the globe of thelight source itself. choose 105 degrees for theother normal, which isthe Hector, because at that point theangl of incidence to the tangentforining the! parabplic is 52jdegrees. Smaller angles 'of incidence areof problcinatical value and we may well call 5%v degrees the criticalangle for the present type of parabolic or spherical reflectors, Areflector of this type will handle approximately 50% of the sphericallight oi" the light er fre. lt is known that the high eiiiciency c L .infilled bulbs is due mainly to the higne: melting and evaporati'ng pointsof matter under pressure in contrast to those invacuum. l't is alsoknown that a gas lilled bulb by convection and radiation carries heataway from the lament, which tends to nega tive current economy.servation of that portion of radiant heat and light that would pass intospace beyond. the aperture or opening` of the concave reflector ifree-focused or returned upon the light source materially raises theoperating' temwhichy having a positive temperature coelicient tends tocurrent economy and greater brilliancy for the beam projected by theconcave reflector.

The spherical aberprojected beam, due to l find that the con- Cri @all

screenyfor lntelfeepilng the central 4the 51%T' l"ee mi the maireflector, t e must m :x

@Waele In accorllunce W'llh tlxls ll pla@ e. @erlie el' @sphericalrelecor between the normals 0l' llljqlflegrees and 135 degrees .andmount an opaque tuben from of lle light source emlnfglcng degrees of thecanelle pow-veln in llle `l'eec@ing surfaces ls used as the base line,the lightfsouree located on the axle as polnl; of ,loclm for the mainreleetor, Ceniz' ofc'ur 'nturele tlm heat relle'clzolr, und mwle ofnormal nterceptefl by the opaque mbe Having llllsfudfltomzl means ofecormmy vi211 heat'nncl llghljwh'eh would otherwise pa.. s

inte Space beyond the pmallel-lveam, l. am illus able to eonomwallyl'educe the aperture el'. the 'parabollc reflector. The front OmU-eeQj'tlle Sphercal mirror by wlx'lch the light fm'lmheat-` are reflectedlmcl: t@ the source preferably equal in diameter *to the apelsme of,lhemain or parallebbeem releclor. The Quxgll oprque tube whlch isplaced in heul', 'of tlle'llght Source represents in optical. e'lelifl,il 'come 0f llel wllezthv' 'lube lms:` cent/alu Speele mlfagee suehesthe olasemng: nl? tl e bei@ "c, spoel which. Woulll otherwise be'vlsl'lle :Stil ihm lll-oud sense be regarded. e"

qu' le @central mi agile-l Screen, 15m" slmtlglng ou@ sa, came. nlllggll' hzwmg llame mi lull@ 'llxe f lmfll lmnp m' secmlalyilllL'lmllml;n ing: Somme which 'is placed in *elle e'lrmlm pocketnelllml lxe mitm-n rel'leelm: is nel sealed from dirent observmnlcmabove ,given level and lle 1li 'from this source will emueu #Self nvslelo ille olzllel. sers el Hw rofu 'l' :um able lo employ vleiglgller:nulle power 'lim' this semnflmfy eomee Wfjlmut :lnconvenlence lio@there and Thus; have 'the Yardage Of: ang/:fle illumination vitlmlizim'usually attendant elljefztenzlole glare in. 1lle eyes u? ll'nosefleeing* the lmnp.

l. A lmnp mmm-lewe e Casing :ated mlrl nmuutell en Sel@ glazing e'ufl lemated su'bstumelly m cul oil' 'l-1m; mll mw locally mgnnlug; "nys :wel elight ism ieee disposed, sullsmutlally al. the 'eeus @il salpm'zmboloicl.

2. A lamp ne described in lalm il? which the sefee'n membel le aCy'llllee tube. l

lllumlxmtng apparatus eemprlsalng., in combination., u Somme 01?. light,a gj),mllel.v beam rellenar eoperatimg 'bhe'fewtllj e my ll'llbl'leeeangular conside alloue lhe. axis oil* d. A, lump a'lmllialrilxxg :lCasing; having; interim reflue-img eulnces emnprlrsmg :L

meme pmjevtlug;fx-electm' and an opposed, pel'plw 'ally loca-nedspherical Zone, e glen? lng' 1m-osea lille lmse ei suld mue and i nervennmlmlml on lle@ Aglazing l'mx'ingf am inwardly exleiulng pmlou faclxngijsazbsantlully lo llxe une flel'lxed my llw, llgll't Source and the lumeel will zum nml mlupliell tu eut el? wllllquely pmmgngefl, .llree 'nys'fram will Somer?. l

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illumination concealed behind said light and heatrectoring moana, forproducing a diffused illumination without visible glare.,

l0. A- vehiclelamp comprising a source of light, a concave relectorpartly enveloping said Source andreiiecting a parallel beam therefrom, asecond reflecting surface surrounding the aperture of said concavereector for returning to said source heat and light falling beyond theangle of the aperture or' 'the first reector, and ormin an annularpocket, and a- Second'eource of light located viiithin said pocket andconcealed by said second reflector.,

ll. l vehicle lampcomprising a light source, a concave .projectingreflector, an opposed periphe ally located return reiecu tor for raysfalling beyond the angle of the aperture of the lirst reflector andforming an. annular ocket, a Screen extending in a generally axialdirection and adapted to cut oil' from Said aperture obliquelypropagated direct rays ,from the light source, a second source of lightlocated Within said pocket and concealed by the return reflector, saidscreen shielding an opposed portion of the concave reflector from raysincident from said Second source.

l2. A. vehicle lamp comprising a Source of light, a concave reflectorpartly enveloping said source and reflecting a parallel beam therefrom,a second reflecting. eurfaceeurrounding the aperture of said concavereflecgardera ture or the first reflector, and forming an annularpocket, said return reflector having a forward central orificecommensurate with the parallel beam and defining with the ceuter of saidlight source a central cone of projection, an axially disposed screen infront of said source, terminating substantially at the imaginary surfaceof such cone of projection, and a Second source of light located Withinsaid pocket and concealed by said second reflector.

13. A vehicle lamp comprising a source of light, a concave reiectorpartly enveloping Said source and reflecting a parallel beam therefrom,a second rclectin surface surrounding the aperture of said concavereflector for returnin to said Source heat and light falling beyon theangle of the aperture of the rst reflector, and forming an an-.

nular pocket, Said return reflector having a forward central orificecommensurate with the parallel beam and defining with the center of saidlight source a central cone of projection, an axially disposed opaquetube 1n front of said Source, terminating substantially at the imaginarysurface of such cone of projection, and a second source of light locatedWithin said pocket and concealed by said second reflector.

Josera T.- norm.

